Flexible biopolymer photodetectors based Er, Tb doped BaW[formula omitted]@CS for enhanced light-sensitive coatings

Abstract

Today, the electro-optics industry is one of the world's largest manufacturing sectors today, and its growth has led to an increasing reliance on electronic equipment. Simultaneously, the significance of optical wearable detection across diverse fields, from high-energy physics to nuclear medicine and optoelectronics, cannot be overstated. Barium tungstate (BWO), a remarkable and advanced compound, has consistently piqued the interest of researchers across various domains due to its unique photoenergy properties. This study presents a novel, cost-effective approach to creating flexible ionizing radiation detectors. These detectors are constructed using pure barium tungstate fillers infused with erbium and terbium within a chitosan matrix (Er: BWO-CS, Tb: BWO-CS). Initially, we synthesized pure barium tungstate nanoparticles, incorporating erbium and terbium through a co-precipitation method, and subsequently embedded them into a chitosan biopolymer substrate. Characterization through XRD, XPS, EDX-MAP, and FTIR analyses confirmed the formation of the tetragonal barium tungstate structure, bonding, compounds, and chemical elements in the prepared composites. Through SRIM calculations, we determined the optimal thickness for these flexible nanocomposites to detect alpha particles, approximating 60–80 micrometers. The optical properties of the detectors were assessed under ultraviolet light excitation, 980 nm laser irradiation, proton beam exposure, and alpha source activation. Notably, the Er: BaWO4-CS nanocomposite exhibited the best scintillation properties, highest UV sensitivity, and superior alpha particle detection efficiency (at a low activity of 643 Bq). The results underscored the stability, reproducibility, and linear response of these sensors under continuous irradiation. Photo/ionoluminescence studies revealed that the doped nanocomposite showed, in comparison to the pure BWO-CS sample, the greatest visible blue-green emission at room temperature, featuring a luminescence delay time of 243 µs. Antimicrobial and cytotoxicity tests confirmed the safety of these flexible sensors, making them suitable for applications related to human health applications. Consequently, these sensors represent a promising avenue for the development of next-generation wearable and environmentally friendly sensing technologies.